In this post, we will show you how to create a new Node JS project with Typescript, customize package.json, install Prettier and ESlint for TypeScript.
Create a new folder for the project
1mkdir ts-project
2cd ts-projectNow, initialize the project
I will use pnpm, but you can use any other package manager you want
1pnpm init I guess it's not surprising ;)
1pnpm i -D typescriptAfter installing typescript, we access the command line of the TypeScript compiler via the tsc command.
Now, it would be good to install surrounding node types in our project to ensure type safety and auto-complete in Node, like file, path, process, etc.
1pnpm i -D @types/nodetsconfig.json - file that defines some parameters for compiling TypeScript into JavaScript.
Now, creating a file
1pnpm exec tsc --initAfter creating the file, the tsconfig.json file should look something like this:
1{
2 "compilerOptions": {
3 /* Basic Options */
4 // "incremental": true, /* Enable incremental compilation */
5 "target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
6 "module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
7 "lib": ["es6"], /* Specify library files to be included in the compilation. */
8 "allowJs": true, /* Allow javascript files to be compiled. */
9 // "checkJs": true, /* Report errors in .js files. */
10 // "jsx": "preserve", /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
11 // "declaration": true, /* Generates corresponding '.d.ts' file. */
12 // "declarationMap": true, /* Generates a sourcemap for each corresponding '.d.ts' file. */
13 // "sourceMap": true, /* Generates corresponding '.map' file. */
14 // "outFile": "./", /* Concatenate and emit output to single file. */
15 "outDir": "build", /* Redirect output structure to the directory. */
16 "rootDir": "src", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
17 // "composite": true, /* Enable project compilation */
18 // "tsBuildInfoFile": "./", /* Specify file to store incremental compilation information */
19 // "removeComments": true, /* Do not emit comments to output. */
20 // "noEmit": true, /* Do not emit outputs. */
21 // "importHelpers": true, /* Import emit helpers from 'tslib'. */
22 // "downlevelIteration": true, /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
23 // "isolatedModules": true, /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
24
25 /* Strict Type-Checking Options */
26 "strict": true, /* Enable all strict type-checking options. */
27 "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */
28 // "strictNullChecks": true, /* Enable strict null checks. */
29 // "strictFunctionTypes": true, /* Enable strict checking of function types. */
30 // "strictBindCallApply": true, /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
31 // "strictPropertyInitialization": true, /* Enable strict checking of property initialization in classes. */
32 // "noImplicitThis": true, /* Raise error on 'this' expressions with an implied 'any' type. */
33 // "alwaysStrict": true, /* Parse in strict mode and emit "use strict" for each source file. */
34
35 /* Additional Checks */
36 // "noUnusedLocals": true, /* Report errors on unused locals. */
37 // "noUnusedParameters": true, /* Report errors on unused parameters. */
38 // "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
39 // "noFallthroughCasesInSwitch": true, /* Report errors for fallthrough cases in switch statement. */
40
41 /* Module Resolution Options */
42 // "moduleResolution": "node", /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
43 // "baseUrl": "./", /* Base directory to resolve non-absolute module names. */
44 // "paths": {}, /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
45 // "rootDirs": [], /* List of root folders whose combined content represents the structure of the project at runtime. */
46 // "typeRoots": [], /* List of folders to include type definitions from. */
47 // "types": [], /* Type declaration files to be included in compilation. */
48 // "allowSyntheticDefaultImports": true, /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
49 "esModuleInterop": true, /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
50 // "preserveSymlinks": true, /* Do not resolve the real path of symlinks. */
51 // "allowUmdGlobalAccess": true, /* Allow accessing UMD globals from modules. */
52
53 /* Source Map Options */
54 // "sourceRoot": "", /* Specify the location where debugger should locate TypeScript files instead of source locations. */
55 // "mapRoot": "", /* Specify the location where debugger should locate map files instead of generated locations. */
56 // "inlineSourceMap": true, /* Emit a single file with source maps instead of having a separate file. */
57 // "inlineSources": true, /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
58
59 /* Experimental Options */
60 // "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */
61 // "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */
62
63 /* Advanced Options */
64 "resolveJsonModule": true /* Include modules imported with '.json' extension */
65 }
66}Let's edit it and clean up the "trash"
1{
2 "compilerOptions": {
3 "module": "commonjs",
4 "esModuleInterop": true,
5 "target": "es2021",
6 "moduleResolution": "node",
7 "strict": true,
8 "sourceMap": true,
9 "lib": ["es2021"],
10 "skipLibCheck": true,
11 "rootDir": "src",
12 "outDir": "dist"
13 }
14}
15module: "commonjs" - node's standard module system in 2019. Let's take advantage of it.esModuleInterpop: true - if you are using the commonjs module system, you need to enable this option.target: "es2021" - ECHMAScript version. I tried to choose between the stable one and the relatively new one.strict: true - strict type checking, please be sure to include it.sourceMap: true - creating one map file instead of several.lib: ["es2021"] - this option adds environment types to our project, allowing us to use features from different versions of ECHMAScript, testing libraries, and even browser DOM features.rootDir: "src" - the main directory of our project. This is where TypeScript will look for our files.outDir: "dist" - output directory. This is where the project will be stored after compilation.We're ready to run our first TypeScript file.
Create a src folder and in it a new file index.ts
1mkdir src
2touch src/index.tsAnd in it we'll write the code
1console.log('Hello world!')To compile the code, we need to run the tsc command with pnpm exec. tsc will read our files in the specified directory and create a compiled version.
1pnpm exec tscCheck out our compiled project in dist/index.js
1"use strict";
2console.log('Hello world!');To run the project in dev mode, we need a couple more packages: ts-node to run TypeScript code directly, without having to wait for it to compile, and nodemon to track changes in our code and automatically restart when a file changes.
1pnpm i -D ts-node nodemonAdd a file nodemon.json
1{
2 "watch": ["src"],
3 "ext": ".ts,.js",
4 "ignore": [],
5 "exec": "npx ts-node ./src/index.ts"
6}
7Add a new script to package.json
1"dev": "pnpm exec nodemon",Now, to run our project in dev mode, just write pnpm dev
To compile the project we need to add a new script to the package.json
1"build": "tsc",Now, after typing pnpm build our project will compile.
Install prettier as dev dependencies
1pnpm i -D prettierCreate a file .prettierrc
1touch .prettierrcLet's insert my favorite text formatting config into the file
1{
2 "useTabs": false,
3 "singleQuote": true,
4 "arrowParens": "avoid",
5 "bracketSpacing": true,
6 "semi": false,
7 "printWidth": 80,
8 "trailingComma": "none",
9 "endOfLine": "lf"
10}
11Let's open package.json and add a new script
1"format": "pnpm exec prettier . --write"Now it is enough to enter pnpm format to make the printer go through all project files (except those specified in .prettierignore).